Self-propelled vacuum cleaner

ABSTRACT

A self-propelled vacuum cleaner comprising: a self-propellable case having a suction opening provided on a bottom surface and an exhaust opening provided at a rear part; and a dust-collecting part provided between the suction opening and the exhaust opening through a ventilation channel, wherein
         the dust-collecting part includes a dust box disposed at the suction-opening side and an electric fan disposed at the exhaust-opening side, and   the dust box and the electric fan are configured to be separable.

TECHNICAL FIELD

The present invention relates to a self-propelled vacuum cleaner.

BACKGROUND ART

As a self-propelled vacuum cleaner for cleaning dust on a floor surface, Patent Document 1 proposes a self-propelled vacuum cleaner including a housing that can be self-propelled and has a suction opening on its lower surface, a main brush mounted to the suction opening so as to be rotatable, and a side brush rotatably mounted anterior to the main brush on the lower surface of the housing.

The self-propelled vacuum cleaner described above includes a rechargeable battery incorporated in the housing and a start/stop switch provided on its top surface. A dust collection unit is detachably mounted at the rear part of the housing.

The dust collection unit includes a dust case having an inflow opening, an exhaust opening, a partition wall separating a space into an inflow side and an exhaust side, and a ventilation hole formed on a part of the partition wall; a filter provided to the ventilation hole; and an electric blower provided in the space of the dust case at the exhaust side.

A pair of positive and negative terminals electrically connected to the rechargeable battery through a lead line is provided at the rear part of the housing, and a pair of metal terminals electrically connected to the electric blower through a lead line is provided to the dust case of the dust collection unit. The positive and negative terminals and the pair of metal terminals are electrically connected to each other in the state in which the dust collection unit is attached to the rear part of the housing.

During driving of the self-propelled vacuum cleaner, dust on a floor surface is flown into the space in the dust case at the inflow side from the suction opening to be collected; and air passes through the filter, whereby the air from which dust is removed is exhausted to the outside from the exhaust opening through the electric blower.

To discard the dust collected in a dust collection space in the dust collection unit, a user removes the dust collection unit from the housing, and throws the dust inside into a dust bin with the inflow opening facing downward. In this case, the dust collection space can be cleaned by use of an accessory brush.

CITATION LIST Patent Document

Patent Document 1: Japanese Unexamined Patent Publication No. 2012-75932

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, in the self-propelled vacuum cleaner described in Patent Document 1, the electric blower and a pair of metal terminals are provided in the dust collection unit, so that the dust case cannot be washed with water. Therefore, fine dust deposited on the dust case cannot completely be removed only with the brush, and it is impossible to sufficiently and perfectly clean the dust case. Since dust is likely to be deposited on the pair of metal terminals as well, there is concern that contact failure between the respective metal terminals and the positive and negative terminals at the housing occurs.

In addition, the self-propelled vacuum cleaner in Patent Document 1 has the structure in which, when the dust case is removed from the housing on a floor surface, the dust in the dust case is likely to be scattered on the floor surface from the inflow opening. This might cause the cleaned floor surface dirty.

The present invention is accomplished in view of the above circumstances, and aims to provide a self-propelled vacuum cleaner provided with a dust collecting part that can be washed with water and is difficult to cause electrical failure.

Means for Solving the Problems

Accordingly, the present invention provides a self-propellable case having a suction opening provided on a bottom surface and an exhaust opening provided at a rear part; and a dust-collecting part provided between the suction opening and the exhaust opening through a ventilation channel, wherein

the dust-collecting part includes a dust box disposed at the suction-opening side and an electric fan disposed at the exhaust-opening side, and

the dust box and the electric fan are configured to be separable.

Effect of the Invention

In the self-propelled vacuum cleaner according to the present invention, the dust box and the electric fan in the dust collecting part is configured to be separable. With this, after the dust box is removed from the case and dust inside is thrown out, the dust box can be washed with water to completely remove fine dust. That is, the dust box can sufficiently be cleaned.

In the configuration in which metal terminals at the dust box are connected to or separated from positive and negative terminals at the case as in the conventional case, dust is likely to be deposited on each terminal, and therefore, there is concern that contact failure between the metal terminals and the positive and negative terminals might occur. However, in the present invention, the configuration for electrically connecting the electric fan to a battery through a lead line can be provided in the case, whereby the above concern can be resolved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a self-propelled vacuum cleaner according to a first embodiment of the present invention.

FIG. 2 is a bottom view of the self-propelled vacuum cleaner according to the first embodiment.

FIG. 3 is a side sectional view illustrating a dust collecting part in the self-propelled vacuum cleaner according to the first embodiment, wherein (A) illustrates a state in which a dust box is mounted, and (B) illustrates a state in which the dust box is removed.

FIG. 4 is a perspective view of the dust box in the self-propelled vacuum cleaner according to the first embodiment.

FIG. 5 is a back view of the self-propelled vacuum cleaner in the state in which the dust box is removed according to the first embodiment.

FIG. 6 is an exploded view of the dust box in the self-propelled vacuum cleaner according to the first embodiment.

FIG. 7 is a side sectional view illustrating a dust collecting part in a self-propelled vacuum cleaner according to a second embodiment.

FIG. 8 is a side sectional view illustrating a dust collecting part in a self-propelled vacuum cleaner according to a third embodiment.

FIG. 9 is a side sectional view illustrating a dust collecting part in a self-propelled vacuum cleaner according to a fourth embodiment.

MODE FOR CARRYING OUT THE INVENTION First Embodiment <Overall Configuration of Self-Propelled Vacuum Cleaner>

FIG. 1 is a plan view illustrating a self-propelled vacuum cleaner according to a first embodiment of the present invention, and FIG. 2 is a bottom view of the self-propelled vacuum cleaner according to the first embodiment. FIG. 3 is a side sectional view illustrating a dust collecting part in the self-propelled vacuum cleaner according to the first embodiment, wherein (A) illustrates a state in which a dust box is mounted, and (B) illustrates a state in which the dust box is removed. FIG. 4 is a perspective view of the dust box in the self-propelled vacuum cleaner according to the first embodiment, FIG. 5 is a back view of the self-propelled vacuum cleaner in the state in which the dust box is removed according to the first embodiment, and FIG. 6 is an exploded view of the dust box in the self-propelled vacuum cleaner according to the first embodiment.

As illustrated in FIGS. 1 to 6, a self-propelled electronic device according to the first embodiment of the present invention is a self-propelled vacuum cleaner 1 that sucks air including dust on a floor surface in a region where the cleaner is placed, while autonomously traveling on the floor surface, and exhausts air from which the dust is removed to thereby clean the floor surface.

The self-propelled vacuum cleaner 1 has a disc-like case 2 provided with a suction opening 6 on its lower surface and storing inside a battery E serving as a power source. Components, such as a rotary brush 9, side brushes 10, a dust collecting part 30 including a dust box 31 and an electric fan 32, a pair of drive wheel units U each including a drive wheel 29, a turnable front wheel 27, various sensors including a floor surface detection sensor 11, and a control board S electrically connected to various sensors, are provided inside and outside of the case 2.

With the self-propelled vacuum cleaner 1, the weight of the self-propelled vacuum cleaner 1 is distributed in front-back direction with respect to the case 2 in order that the weight can be supported by a pair of drive wheels 29, which is mounted to the case 2 at the middle position in the front-back direction, and the front wheel 27.

The case 2 has a bottom plate 2 a that is approximately circular in a plan view and has a suction opening 6 formed at the position backward from the middle position in the front-back direction, a top plate 2 b having a start/stop button 3 on a central position, and a side plate 2 c that is annular in a plan view and formed along outer peripheries of the bottom plate 2 a and the top plate 2 b. The bottom plate 2 a is provided with a plurality of holes from which a pair of drive wheels 29 projects to the outside from the case 2, and an exhaust opening 7 is formed at the rear part of the side plate 2 c. Notably, the side plate 2 c is split into two which are a front part and a rear part, and the front part of the side plate functions as a bumper.

The suction opening 6 is a recessed open surface formed on the bottom surface (lower surface of the bottom plate 2 a) of the case 2 so as to face a floor surface K. The rotary brush 9 rotating about a shaft center parallel to the bottom surface of the case 2 is provided in the suction opening 6. Side brushes 10 rotating about a perpendicular rotation shaft center are provided at both of left and right sides of the suction opening 6. The rotary brush 9 is formed such that brushes are helically implanted on an outer peripheral surface of a roller serving as the rotation shaft. Each of the side brushes 10 is formed such that a brush bundle is radially provided at a lower end of the rotation shaft. The rotation shaft of the rotary brush 9 and the rotation shafts of a pair of side brushes 10 are pivoted to a part of the bottom plate 2 a of the case 2, and coupled with a drive motor provided in the vicinity thereof through a power transmission mechanism including a pulley and a belt.

As illustrated in FIG. 2, floor surface detection sensors 11 are disposed in front of the front wheel 27 and at a front side at the side of left and right drive wheels 29 on the bottom surface of the case 2. When the floor surface detection sensors 11 sense descending stairs, the sensing signals from the sensors 11 are transmitted to a control unit, and the control unit provided to the control board S controls to stop both drive wheels 29.

The control board S includes a control circuit that controls each of the components such as the drive wheels 29, the rotary brush 9, the side brushes 10, and the electric fan 32 in the self-propelled vacuum cleaner 1.

The self-propelled vacuum cleaner 1 moves forward by forward rotations of the left and right drive wheels 29 in the same direction, moves backward by reverse rotations in the same direction, and turns with the rotations in the opposite direction. For example, the self-propelled vacuum cleaner 1 stops the drive wheels 29, and changes its direction by rotating the left and right drive wheels 29 in the opposite direction, in the case where the self-propelled vacuum cleaner 1 reaches an edge of an area to be cleaned and in the case where the self-propelled vacuum cleaner 1 collides against an obstacle on a traveling route. In this way, the self-propelled vacuum cleaner 1 autonomously travels, while avoiding obstacles throughout the entire region where the self-propelled vacuum cleaner 1 is placed or the entire desired range.

<Dust Collecting Part>

As illustrated in FIG. 3(A), the dust collecting part 30 is provided between the suction opening 6 and the exhaust opening 7 through a ventilation channel in the case 2. It is to be noted that FIGS. 3(A) and (B) do not illustrate the structure anterior to the dust collecting part 30.

The dust collecting part 30 includes a dust box 31 disposed at the side of the suction opening 6 and an electric fan 32 disposed at the side of the exhaust opening 7, the dust box 31 and the electric fan 32 being configured to be separable. Specifically, the electric fan 32 is disposed in the case 2, and the dust box 31 is detachably disposed at the rear part of the case 2.

The structure of the dust collecting part 30 and the ventilation channel will be specifically described. Firstly, the case 2 has a rear opening 5 formed by cutting a lower half of the rear part of the side plate 2 c. The rear opening 5 is an opening into which the dust box 31 is fitted, and the detail thereof will be described later.

The case 2 also includes an upstream ventilation channel 6 a which allows the suction opening 6 and the rear opening 5 to communicate with each other, a downstream ventilation channel 7 a which allows the exhaust opening 7 and the rear opening 5 to communicate with each other, a first packing 8 a provided around a first connection opening 5 a of the upstream ventilation channel 6 a at the side of the rear opening 5, and a second packing 8 b provided around a second connection opening 5 b of the downstream ventilation channel 7 a at the side of the rear opening 5.

The first packing 8 a is made of a rubber ring. For example, it is attached around the first connection opening 5 a with bonding by way of an adhesive agent, or with fitting around an annular projection part formed around the first connection opening 5 a.

The second packing 8 b is also made of a rubber ring. For example, it is also attached around the second connection opening 5 b by way of an adhesive agent, or with fitting around an annular projection part formed around the second connection opening 5 b.

The electric fan 32 is fixed in the downstream ventilation channel 7 a which defines an upper space of the rear opening 5 in the case 2. An inlet opening of the electric fan 32 is disposed close to the second connection opening 5 b, and a discharge opening of the electric fan 32 is disposed close to the exhaust opening 7.

As illustrated in FIG. 6, the dust box 31 includes a lower case 31A, a filter case 31B, a filter 31C, and an upper case 31D, wherein the filter case 31B storing the filter 31C is sandwiched between the upper case 31D and the lower case 31A.

The lower case 31A is open at the top, and has a bottom wall 31Aa in which one of a pair of long sides of a rectangle expands outward and a surrounding wall 31Ab stands along an outer peripheral edge of the bottom wall 31Aa. An inner step part 31Ab₁ exposed at the top side is provided on the inner peripheral surface of the surrounding wall 31Ab, an outer step part 31Ab₂ (see FIG. 3(B)) exposed at the bottom side is provided on the outer peripheral surface of the surrounding wall 31Ab, and an inflow opening 31Ab₃ connectable to the first connection opening 5 a through the first packing 8 a is formed on the front surface of the surrounding wall 31Ab below the outer step part 31Ab₂.

The filter case 31B includes a frame part 31Ba that is supported by the inner step part 31Ab₁ when the filter case 31B is stored in the lower case 31A, and a lattice part 31Bb provided in the frame part 31Ba to support the filter 31C.

The filter 31C is formed to have a size by which the filter 31C is tightly fitted into the frame part 31Ba of the filter case 31B. For example, an HEPA filter can be used for the filter 31C. Notably, the filter 31C may be integrally formed with the filter case 31B.

The upper case 31D is a lid covering an upper opening of the lower case 31A, and includes an upper wall 31Da, a surrounding wall 31 Db, and an engagement member 31Dc provided at the rear part of the upper wall 31Da.

The middle part of the upper wall 31Da in the horizontal direction tilts downward from the rear side to the front side to be recessed, and a discharge opening 31Da₂ connectable to the second connection opening 5 b through the second packing 8 b is formed on a recessed tilt part 31Da₁. The top surface of the tilt part 31Da₁ defines a tilt upper surface 31Da₁₁.

The engagement member 31Dc is an elastically deformable member projecting to bend rearward from the rear part of the upper wall 31Da. An engagement projection 31Dc₁ with a triangular cross-section is formed on its top surface.

In the dust box 31 thus configured, the filter 31C is disposed between the inflow opening 31Ab₃ and the discharge opening 31Da₂, and a dust collecting chamber 31Ac is formed between the inflow opening 31Ab₃ and the filter 31C.

The rear opening 5 is configured as described below in order to attach the dust box 31 to the rear opening 5 of the case 2 without falling off.

The rear opening 5 has a tilt lower surface 2 d which tilts downward toward the front side and is formed on the ceiling part of the rear opening 5, that is, on the part where the second packing 8 is provided; and horizontal lower surfaces 2 e at both sides of the tilt lower surface 2 d.

The rear opening 5 also has an inner wall 2 f where the first packing 8 a is provided, and left and right side walls 2 g at the left and right of the inner wall 2 f. Left and right step parts 2 g ₁ supporting the outer step part 31Ab₂ of the dust box 31 are formed on the left and right side walls 2 g. In addition, a space into which the engagement member 31Dc of the dust box 31 is stored is formed at the back of the tilt lower surface 2 d of the rear opening 5, and an engagement recess 2 d ₁ is formed on the ceiling part of the space, wherein the engagement projection 31Dc₁ of the engagement member 31Dc can be engaged with or disengaged from the engagement recess 2 d ₁.

When the dust box 31 removed from the case 2 (see FIG. 3(B)) is attached to the rear opening 5, the left and right outer step parts 31Ab₂ of the dust box 31 slide on the left and right step parts 2 g ₁ of the rear opening 5. When the dust box 31 is pushed all the way into the rear opening 5, the front surface of the surrounding wall 31Ab of the dust box 31 is in close contact with the first packing 8 a (see FIG. 3(A)).

Also in this case, the tilt upper surface 31Da₁₁ of the dust box 31 is in close contact with the second packing 8 b, and the engagement projection 31Dc₁ rides over the side plate 2 c of the case 2 to be engaged with the engagement recess 2 d ₁ due to the elastic deformation of the engagement member 31Dc. With this, the dust box 31 is mounted into the rear opening 5 of the case 2 without falling off.

In the self-propelled vacuum cleaner 1 to which the dust box 31 is mounted, the electric fan 32, the drive wheels 29, the rotary brush 9, and the side brushes 10 are driven according to an instruction of a cleaning operation. With this, the self-propelled vacuum cleaner 1 sucks air containing dust on the floor surface K from the suction opening 6 with the state in which the rotary brush 9, the side brushes 10, the drive wheels 29, and the front wheel 27 are in contact with the floor surface K, while the case 2 autonomously travels within a predetermined range. In this case, dust on the floor surface K is swirled up with the rotation of the rotary brush 9, and guided to the suction opening 6. Further, dust at the side of the suction opening 6 is guided to the suction opening 6 with the rotation of the side brushes 10.

As illustrated in FIG. 3(A), air containing dust D sucked into the case 2 through the suction opening 6 passes through the upstream ventilation channel 6 a in the case 2 to flow into the dust collecting chamber 31Ac of the dust collecting part 30. Air flow going into the dust collecting chamber 31Ac passes through the filter 31c and the electric fan 32, and then, is discharged to the outside from the exhaust opening 7 through the downstream ventilation channel 7 a. In this case, the dust D contained in the air flow in the dust collecting chamber 31Ac is caught by the filter 31C, whereby the dust D is accumulated in the dust collecting chamber 31Ac.

To discard the dust D in the dust box 31, the user draws the dust box 31 backward, while releasing the engagement projection 31Dc₁ from the engagement recess 2 d ₁ by pressing the engagement member 31Dc₁. Then, the user removes the upper case 31D and the filter case 31B storing the filter 31C from the lower case 31A of the dust box 31, and throws away the dust D in the lower case 31A into a dust bin.

According to the self-propelled vacuum cleaner of the present invention, the electric fan 32 in the dust collecting part 30 is separated from the dust box 31 in this case, whereby the dust box 31 can be washed with water. Notably, the filter 31C may be cleaned with a brush, and further be washed with water in this case.

Second Embodiment

FIG. 7 is a side sectional view illustrating a dust collecting part of a self-propelled vacuum cleaner according to a second embodiment. In FIG. 7, the components same as those in FIGS. 1 to 6 are identified by the same reference numerals.

The self-propelled vacuum cleaner according to the second embodiment is similar to the first embodiment except for the configuration of a dust collecting part 130.

The second embodiment is different from the first embodiment in that a dust box 131 has a dust leak prevention member 131Ab₄ that is provided at the inflow opening 31Ab₃ for preventing the dust D in the dust collecting chamber 31Ac of the dust box 131 from leaking and falling from the inflow opening 31Ab₃. In the second embodiment, the dust leak prevention member 131Ab₄ projecting obliquely upward from the lower end of the inflow opening 31Ab₃ to the inner side is provided.

Since the dust leak prevention member 131Ab₄ is provided, the dust D accumulated in the dust collecting chamber 31Ac is difficult to leak and fall from the inflow opening 31Ab₃ to the outside when the dust box 131 is removed from the case 2. Therefore, mistake of causing the cleaned room dirty with scattering dust D can be reduced.

Third Embodiment

FIG. 8 is a side sectional view illustrating a dust collecting part of a self-propelled vacuum cleaner according to a third embodiment. In FIG. 8, the components same as those in FIG. 7 are identified by the same reference numerals.

The self-propelled vacuum cleaner according to the third embodiment is similar to the first and second embodiments except for the configuration of a dust collecting part 230.

In the third embodiment, a dust leak prevention member 231Ab₄ different from the dust leak prevention member 131Ab₄ in the second embodiment is provided to the inflow opening 31Ab₃. The dust leak prevention member 231Ab₄ horizontally projects from the upper end of the inflow opening 31Ab₃ toward the inner side, and extends downward to form an inverted L shape.

With the formation of the dust leak prevention member 231Ab₄ as well, leakage and falling of the dust D from the inflow opening 31Ab₃ upon removing the dust box 131 from the case 2 can be prevented as in the second embodiment.

Fourth Embodiment

FIG. 9 is a side sectional view illustrating a dust collecting part of a self-propelled vacuum cleaner according to a fourth embodiment. In FIG. 9, the components same as those in FIG. 7 are identified by the same reference numerals.

The self-propelled vacuum cleaner according to the fourth embodiment is similar to the first to third embodiments except for the configuration of a dust collecting part 330.

In the fourth embodiment, a dust leak prevention member 331Ab₄ corresponding to the dust leak prevention member 131Ab₄ in the second embodiment is provided at the lower end of the inflow opening 31Ab₃, and a dust leak prevention member 331Ab₅ corresponding to the dust leak prevention member 231Ab₄ is provided at the upper end of the inflow opening 31Ab₃.

As in the second and third embodiments, the fourth embodiment can also prevent the dust D from leaking and falling from the inflow opening 31Ab₃ upon removing the dust box 131 from the case 2.

Fifth Embodiment

In the self-propelled vacuum cleaner according to the present invention, the rotary brush 9 and the side brushes 10 described in the first embodiment are not required components, so that they may be eliminated.

(Summary)

A self-propelled vacuum cleaner according to the present invention includes a self-propellable case having a suction opening provided on a bottom surface and an exhaust opening provided at a rear part; and a dust-collecting part provided between the suction opening and the exhaust opening through a ventilation channel, wherein

the dust-collecting part includes a dust box disposed at the suction-opening side and an electric fan disposed at the exhaust-opening side, and

the dust box and the electric fan are configured to be separable.

The self-propelled vacuum cleaner according to the present invention may be configured as described below.

(1) In the dust collecting part, the electric fan may be disposed in the case, and the dust box may be detachably mounted to the rear part of the case.

With this configuration, a battery that is a heavy load can be disposed at a front part of the case, whereby the center of gravity can be placed on the front part of the case. This results in supporting the case with a pair of left and right drive wheels and a front wheel, whereby a rear wheel can be eliminated.

(2) The case may include a rear opening into which the dust box is fitted, an upstream ventilation channel that allows the suction opening and the rear opening to communicate with each other, a downstream ventilation channel that allows the exhaust opening and the rear opening to communicate with each other, a first packing provided around a first connection opening of the upstream ventilation channel at the rear-opening side, and a second packing provided around a second connection opening of the downstream ventilation channel at the rear-opening side,

the electric fan may be disposed in the downstream ventilation channel, and

the dust box may include an inflow opening connectable to the first connection opening through the first packing, a discharge opening connectable to the second connection opening through the second packing, a filter provided between the inflow opening and the discharge opening, and a dust collecting chamber provided between the inflow opening and the filter.

With this configuration, the ventilation channel from the suction opening to the exhaust opening can be shortened, which is advantageous for suppressing a load on the electric fan.

(3) The case may have a tilt lower surface tilting downward toward a front side at the portion where the second packing is provided, and

the dust box may have a tilt upper surface tilting downward toward a front side at the portion where the discharge opening is formed.

With this configuration, the surrounding of the discharge opening on the tilt upper surface of the dust box can easily be brought into close contact with the second packing upon mounting the dust box. In this case, with the configuration in which the tilt lower surface is formed on the case and the tilt upper surface is formed on the dust box, a problem of abrasion or falling of the second packing due to scrape of the other parts of the dust box with the second packing can be avoided.

(4) The dust box may have a dust fall prevention member provided at the inflow opening for preventing dust in the dust box from leaking and falling from the inflow opening.

With this configuration, dust in the dust box is difficult to leak and fall from the inflow opening onto a floor surface upon removing the dust box from the case on the floor surface. This can prevent mistake of causing the cleaned floor surface dirty.

The embodiments of the present invention described above should be considered in all respects as illustrative and not restrictive of the present invention. The scope of the present invention is not limited to the above description, but the accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.

EXPLANATION OF NUMERALS

-   2 Case -   2 d Tilt lower surface -   5 Rear opening -   5 a First connection opening -   5 b Second connection opening -   6 Suction opening -   6 a Upstream ventilation channel -   7 Exhaust opening -   7 a Downstream ventilation channel -   8 a First packing -   8 b Second packing -   30, 130, 230, 330 Dust collecting part -   31, 131, 231, 331 Dust box -   31Ab₃ Inflow opening -   31Ac Dust collecting chamber -   31C Filter -   31Da₁₁ Tilt upper surface -   31Da₂ Discharge opening -   32 Electric fan -   131Ab₄, 231Ab₄, 331Ab₄, 331Ab₅ Dust fall prevention member 

1. A self-propelled vacuum cleaner comprising: a self-propellable case having a suction opening provided on a bottom surface and an exhaust opening provided at a rear part; and a dust-collecting part provided between the suction opening and the exhaust opening through a ventilation channel, wherein the dust-collecting part includes a dust box disposed at the suction-opening side and an electric fan disposed at the exhaust-opening side, and the dust box and the electric fan are configured to be separable.
 2. The self-propelled vacuum cleaner according to claim 1, wherein the electric fan is disposed in the case, and the dust box is detachably mounted to the rear part of the case in the dust collecting part.
 3. The self-propelled vacuum cleaner according to claim 2, wherein the case includes a rear opening into which the dust box is fitted, an upstream ventilation channel that allows the suction opening and the rear opening to communicate with each other, a downstream ventilation channel that allows the exhaust opening and the rear opening to communicate with each other, a first packing provided around a first connection opening of the upstream ventilation channel at the rear-opening side, and a second packing provided around a second connection opening of the downstream ventilation channel at the rear-opening side, the electric fan is disposed in the downstream ventilation channel, and the dust box includes an inflow opening connectable to the first connection opening through the first packing, a discharge opening connectable to the second connection opening through the second packing, a filter provided between the inflow opening and the discharge opening, and a dust collecting chamber provided between the inflow opening and the filter.
 4. The self-propelled vacuum cleaner according to claim 3, wherein the case has a tilt lower surface tilting downward toward a front side at the portion where the second packing is provided, and the dust box has a tilt upper surface tilting downward toward a front side at the portion where the discharge opening is formed.
 5. The self-propelled vacuum cleaner according to claim 3, wherein the dust box has a dust fall prevention member provided at the inflow opening for preventing dust in the dust box from leaking and falling from the inflow opening. 